Buckles have been conventionally used as a means for connecting/disconnecting two ends of a cord-like member, or connecting/disconnecting two cord-like members. A conventional buckle includes a plug and a socket connected to each other in a predetermined connecting direction, and a connecting mechanism between the plug and the socket for connecting the plug and the socket to each other. The connecting mechanism has an operating section. The plug and the socket are disconnected by an external operation of the operating section. Most buckles have a flattened shape whose thickness is smaller than its length in the connecting direction and its width.
There exist cases where tensile loads are applied from the cord-like members respectively attached to the buckle and the socket to try to separate the connected plug and the socket from each other along the connecting direction.
Buckles include a front release type buckle in which the operating section is provided on its front face. The front release type buckle is disconnected by pressing the operating section toward its back face side (refer to, for example, Patent Document 1).
The connecting mechanism of the front release type buckle includes a tongue-like portion extending in the connecting direction from a base end portion of the plug, a biasing section for biasing the tongue-like portion toward the back face side of the buckle, a locking projection (operation section) projecting in the thickness direction from a tip end portion of a front face of the tongue-like portion and having a locked face along the thickness direction, an insertion hole formed in the socket along the connecting direction and having an opening in a tip end portion thereof, and a locking stepped portion formed on a front face side of the insertion hole and having a locking face along the thickness direction.
The tongue-like portion has a plate-like shape whose thickness is smaller than its length in the connecting direction and its width. The tongue-like portion can be slightly elastically deformed in the thickness direction by pressing the locking projection toward the back face side of the buckle.
In the buckle according to Patent Document 1, the tongue-like portion of the plug is inserted into the insertion hole of the socket, and the buckle is connected by engaging the locked face of the tongue-like portion and the locking face of the insertion hole with each other. When the buckle is in a connected state, the tongue-like portion is biased by the biasing section toward the front face side of the buckle inside the insertion hole, and the locked face and the locking face abut against each other face-to-face.
To disconnect such connected buckle, a user presses the locking projection toward the back face side of the buckle to deform the tip end portion of the tongue-like portion toward the back face side of the buckle. Accordingly, since the locked face is also moved toward the back face side of the buckle, the engagement between the locked face and the locking face is released. Then, all the user needs to do is to keep the locking projection pressed and separate the plug and the socket from each other along the connecting direction.
[Patent Document 1] U.S. Pat. No. 5,440,792